1. Field of the Invention
The present invention relates to a clamp for a concrete form to hold and fix a connection part of a wooden concrete form to be installed in advance in concrete placement work.
2. Description of the Related Art
A P-clamp utilizing a steel cam mechanism used in connecting plastic forms has been available, and the P-clamp itself is an application of a clamp used for connecting general wooden forms together.
However, such conventional P-clamps are not durable, or they are very weak against vibrations necessarily produced by a vibrator when the concrete is placed. In other words, the conventional P-clamps are not durable because they get over a stopper while a lever of the P-clamp is used, thus causing trouble in subsequent use. This occurs when the lever is turned not only by hand but also by a tool. Thus, this trouble cannot be solved in practice when many workers use the P-clamp by strictly observing the rules of use. Still worse, the stopper cannot be improved from the point of view of a cost.
Regarding the weakness against vibrations, a vibrator is operated to obtain a firm concrete periphery when the concrete is placed, and the P-clamp, which itself is assembled with a form connection part of a form, is loosened by vibrations of the vibrator. Therefore, workers must frequently re-tighten the P-clamp while checking the condition of the P-clamp, which is very troublesome in terms of work efficiency.